Quantum chemistry study of symmetric methyne substitution patterns in the boron buckyball

We report the electronic structure of methyne boron buckyballs B68(CH)12, B72(CH)8 and B76(CH)4 obtained by substituting, respectively, 12, 8 and 4 boron cap atoms by methyne CH groups on the boron buckyball B80. DFT calculations and minimization techniques have been employed to characterize the structural and electronic properties of endo and exo isomers of these molecules in Th and T symmetry. A vibrational frequencies analysis predicts that only endo-B72(CH)8 and endo-B76(CH)4 correspond to a true minimum on the potential energy hypersurface with a cohesive energy similar to the boron buckyball. The stable substitutions are characterized by six rhombohedral B4 bonding motifs.